Hermetic sealing of tins or like receptacles.



No. 708,868. Patented Sept. 9, I902.

.1. n. CROFT.

HEBMETIC SEALING 0F TINS 0B LIKE RECEPTACLES.

(Application filed June 4 1901 (No Model.)

TNE NORIUS PETERS 20.. Pnbrauma. wuumo'ran. n. c.

UNITED STATES PATENT OFFICE.

JOHN RADOLIFFE CROFT, OF LONDON, ENGLAND, ASSIGNOR TO VALVES,

LIMITED, OF LONDON, ENGLAND.

HERMETIC SEALING OF TINS OR LIKE RECEPTACLES.

SPECIFICATION forming part of Letters Patent No. 708,868, datedSeptember 9, 1902.

Application filed J 11116 4. 1901. Serial No. 63.140. (No model.)

To aZZ whom, it may concern-.-

Beit known that I, JOHN RADGLIFFE CROFT, a subject of the King of GreatBritain and Ireland, and a resident of 20 Mark Lane, in

the city of London, England, have invented certain new and usefulImprovements in the Hermetic Sealing of Tins or Like Receptacles, (forwhich I have made application for patent in 'GreatBritain, datedNovember 16, 1900,)

I0 of which the following is a specification.

My invention relates to the hermetic sealing of tins and otherreceptacles for the preservation of alimentary and other substances.

Great difficulty has hitherto been experienced in effecting asatisfactory hermetic closure of receptacles containingalimentarysubstances for preservation; and the object of my invention isto provide improved means by which an effective and reliable hermetic 2oclosure may be obtained.

Without going through the various details of the well-known hot-bath andretort processes for the preservation of alimentary and other substancesin receptacles hitherto in use it may be stated that the principaldefects and causes of failure are due to the fact that during theprocesses a diiference of pressure exists except for an instant betweenthe inside and outside of the receptacles and that the application ofthe solder or other sealing material is only effected in an atmospherenot sterile and after the pressure has become greater outside thaninside the receptacle, and the consequence is that prior 5 to theclosing of the tins or receptacles a certain quantity of air has 'foundaccess to the receptacle before the seal is effected. To provide againstthe bad results of this readmission of air the receptacles are subjectedto 0 a second application of heat, which has a very detrimental effectupon the contents when of a certain class, the said contents be ing inmost cases overcooked. N ow according to my invention I cause thesealing material to act and effect a closure automatically andwithoutremoval of the receptacles from the sterile chamber, whether itbe a bath, retort, or vacuu m-chamber. The solder or sealing materialwhich I employ and the position in which it is placed, together with theconstruction of the venting-aperture of the tins or receptacles, is suchthat all air in the receptacles or steam and vapor generated from rangedor determined as to require a variation of but a few degrees from thatrequired to sterilize or cook the contents of the receptacle, the casemay be. What are known as fusible metals, which melt at low tem-.peratures, are especially suitable as a solder for use with the sealingdevice hereinafter described. I am also by my invention enabled toemploy a cold vacuum or sterile chamber for exhausting the air from thereceptacles, and in such a process it is convenient to use paraffin-waxor like sealing material having a low melting-point, although metalsolder may be employed, if required. The improved receptacle I employ isprovided with a venting-aperture situated in or connected to a recess,pipe, chamber, or other part adapted to receive the sealing material. 80 The said recess, pipe, or chamber is provided with a cap or valveadapted to be stopped by the sealing material when melted and is alsoprovided with a plug or stop made of porous material or fabric adaptedto pass air, but to deter the passage of the sealing material.

In the accompanying drawings, Figure 1 is a cross-section of anarrangement of valve or. venting-aperture, hereinafter referred to asthe venting and sealing device, which I c find most suitable. Figs. 2,3, and 4 are similar views to Fig. 1, showing varied arrangements of thesealing material and plugging material. Fig. 5 is a similar view to Fig.1, showing a modified shape of the venting and 5 sealing device. Fig. 6is a similar view showing a modified construction of venting and sealingdevice which I-fiud suitable for the retort process. Fig. 7 shows amodified con-.

struction of Fig. 6.

The venting and sealing device now described is formed by stamping forconvenience and cheapness of manufacture and com- I prises a well 0,stamped in the top of the tin l and having formed around its edge aledge (l and outside the ledge a gutter e. The well 0 is capped by acover f, formed with dished part c adapted to depend into the well 0,and a beveled edge 71 to depend into the gutter e, the intervening flatpart 6 corresponding to ledge d. The cover f has a venting-apertu re 'atthe base of the depending part 9 and opening into the well 0, and theledge d has one or a number of holes is formed therein and opening intothe tin. In use a plug formed by a disk of porous material orfabric-such as filtering-paper in the form of a disk Z, Fig. 1, orannulus l, Figs. 2 and 4, or disk 1* with hole Z as in Fig. 3is placedin the well 0, so as to cover the holes 7; in the ledge (Z. The coverfisthen placed in position,and its beveled edge his soldered to the tin inthe gutter e. A sufficient quantity of solder or sealing material isplaced in the dished part g, and for convenience it may be meltedthereonto, as indicated at m, orit may be granular or other suitableform.

In Fig. 4 the venting and sealing device is constructed in a similarmanner to that shown in Fig. 1; but the solder, in the form of a disk offoil or sheet metal, is placed in the well 0 between same and the coverf, as at m. In this case the paper plug is in the form of an annulus Z,covering the holes 7a.

In the modified form of the venting and sealing device shown in Figs. 6and 7 an additional cover 72, is provided, formed with a dish part 0,beveled edge 13, and flat part q, corresponding to the similar parts g72 iof the coverf, and in this arrangement the part (1 is perforatedwith one or more venting-holes 'r, and in this case the bottom of thewell a and 'coverf are recessed, as at c and f, respectively, and thesolder or sealing material is put into the top recess f. One plug ofpaper or porous material 1 in the form of a disk is laid between well 0and cover f, and another porous plug Z is placed between the covers fand n, and the edges h p are soldered together and to the tin in thegutter c. In the form shown in Fig. 7 the recesses f and c are dispensedwith and the outer cover 1?. is stamped with an annular kink 'n, adaptedto press upon and clamp the porous plugs tightly between the covers. Inthis arrangement the sealing material is arranged below the kink andwill be stamped out of thin sheets, so as to lie tightly between the twocovers f and n, at on.

The well 0 instead of being of dish shape, as shown in Figs. 1 to 4-,may be made of conical form, as shown in Fig. 5, so that the part wherethe solder is received will approach as near as possible to the globularform the molten solder tends to assume.

I will now describe one method carried out in accordance with myinvention where a hotbath process is employed and the tins are entirelycovered with water.

The tins to be sealed being fitted and prepared as described, say, inFig. .1 are placed in the hot bath, where they are covered with wateror, as in. some processes at present in use, a solution of calciumchlorid. Further heat is now applied, as by means of steam introd needto the bath, by which means the contents of the tins are cooked orsterilized and the sealing material is. melted, while the air containedin the tins is driven out by and together with the vapor generatedtherein. The air and vapors pass out through the hole or holes 7t, pastor through the plug Z, and out through the hole and will pass or bubblethrough the melted solder. As soon as the contents of the tins have beentreated for a suflicient period and the air has been driven out of thetins then the sealing is automatically effected by cooling the bathbelow the setting temperature of the solder or sealing material. Shouldthe solder be forced through the holej by the outside pressure, theplugl deters its passage, and the solder sets in the space between thewell 0 and dished part g and effectually closes the venting device. Ifind that with a venting device such as shown in Fig. 1 and with thebath process described a suitable melting-point for the solder would befrom 200 to 212 Fahrenheit.

Tins or other receptacles with vents, such as herein described, may alsobe employed for hermetic sealingby the hot-bath processes where the topsof the tins and venting-apertures are exposed to the air, the action ofthe venting and sealing device being similar. Where a retort isemployed, the tins are placed in the retort, which is now closed, exceptfor an outlet-pipe, and heat is appliedsay by steam introduced byasuitable pipeand the tins are subjected to a temperature of 212. Thesolder is thus melted, and the air and vapors from the contents of thetins pass out through the venting and sealing device, as beforedescribcd in reference to the bath process, and the introduced steampasses out with the air and vapors from the tins through the outlet. Theretort may now be allowed to cool to seal the tins, as described, orbefore allowing the tins to be sealed the retort may be closed for thepurpose of raising the temperature to any suitable degree.

Referring now to the application of my invention so as to enable avacuum or cold process to be used, as in cases where it is not requiredto cook the articles to be preserved, the receptacles to be sealed arefitted with venting and sealing devices, such as herein described, andwith a sealing material having a low melting-point. For very lowtemperature I may employ paraffin-Wax, ceresin, animal fats, or thelike. The tins are placed in the vacuum-chamber and the air is exhaustedtherefrom bysuitable means,such as a vacuum-pump, then gasessuch ascarbonicacid gas, nitric oxid, or innocuous gases, or gases calculatedto prevent the growth of the microbes of decomposition, and thereforethe sees as formation of poisonous products-are intro duced andwithdrawn one or more times to further insure the extraction andneutralization of the air in the chamber and the tins. Then the vacuumchamber is brought to a temperature sufficient to melt the sealingmaterial, which on cooling sets and covers and sealsthe venting device.The tins can now be safely removed from the vacuum-chamber, and in orderto provide a permanent seal not i so liable to destruction as the waxordinary solder may, if required,be applied to the venting aperture orapertures. I find. that paraffin-wax melting at a temperature of 115Fahrenheit is suitable for the vacuum process, and if a fusible metalsolder is employed its melting-point may be about 125 Fahreneit.

I amaware that prior to the date of my patent attempts have been made toprovide for the automatic sealing of cans for preserved food and othersubstances by the use of fusible sealing materials; but so far as I amaware all such attempts have been unsuccessful, owing to the difficultyof so constructing the seal that the air and vapors could freely passout of the vessel while cooking was going on, and yet the fusiblesealing material could not pass into the vessel ,upon cooling. Thisdifficulty I have met by my combination of parts, as hereinbeforedescribed. It is of course apparent that the arrangement of internal andexternal ventingholes with an interposed porous material which permitsthe passage of the air and vapor out of the tin, but whichprevents theinflow of the molten sealing material into the tin, can be diiferentlyarranged without departing from the spirit of my invention.

It will be evident from the foregoing description, taken in connectionwith the drawings, that my invention embraces a can-clos-. ing deviceconsisting of a plurality of superposed parts having outlets andtheoutlets being out of. line, means for separating said parts, and afusible seal for one of the outlets.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is-- I 1. A can-closing device consisting of aplurality of superposed parts having outlets, the outlets being out ofline, an intermediate porous section, and a fusible seal for one of theoutlets.

2. A can-closing device consisting of a plurality of superposed partshaving outlets, the outlets being out of line, an intermediate poroussection, and a seal of fusible metal solder for one of said outlets.

3. Acan-closingdeviceincludinga plurality of superposed metallic andsubstantially similarly concaved parts, the concavity of an upper partlying in the concavity of a lower part and the latter directlysupporting the former, and said parts having outlets and the outletsbeing out of line whereby fusible material'applied to an outlet of saidupper part will be arrestedfrom downflow by said lower part.

4.. Acan-closingdeviceincludingaplurality of superposed metallic andsubstantially similarly concavedparts, the concavity of an upper partlying in the concavity of a lower part and the latter directlysupporting the former, and said parts having outlets and the outletsbeing out of line whereby fusible materialapplied to an outlet of saidupper part will be arrested from downflow by said lower part, and apiece of porous material held in place by and between said metallicparts.

5. A can closing device including a part having a concaved portion asecond part having an opening located over said concaved portion, apiece of porous material between said parts, and a fusible seal for saidopening.

6. A can-closing device consisting of a plurality of superposed partsthe lower one being concaved and the upper one having an opening oversaid concaved portion and a fusible seal for said opening.

7. A can-closing'device including a part having innerand outer concavedportions and an intermediate raised portion said inner concaved portionhaving a hole provided with a fusible seal and a second part having aconcaved portion located over the inner concaved portion and a beveledportion arranged to fit into the concaved portion of the first-mentionedpart. g

8. A can-closing device including a part havinginner and outer concavedportions andan intermediate raised portion, a second part said partsbeing superposed and the upper one having a hole provided with a fusibleseal having a concaved portion located over the inner concaved portionand a beveled portion arranged to fit into the concaved portion of thefirst-mentioned part, and a pieceof porous material between said parts.

9. A can-closing device including a part having inner and outer concavedport-ions and an intermediate raised portion, a second part having aconcaved portion located over the inner concaved portion and a beveledportion arranged to fit into the concaved portion of the first-mentionedpart,a piece of porous material between the parts, the latter havingnon-registering openings, and a fusible seal for one of the openings.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

JOHN RADOLIFFE CROFT.

